Note: The
information architect had to declare all the parameter entities that are referenced in
the redefined attributes for
section. If he did not do so, none of the attributes that are
declared in the conref-atts,
select-atts, or
localization-atts parameter entities would be
available on the section element. Furthermore, since the
select-atts parameter entity references the
filter-atts parameter entity, the
filter-atts must be declared and it must precede
the declaration for the select-atts parameter entity.
The
props-attribute-extensions and
base-attribute-extensions parameter entities do
not need to be declared in the constraint module, because they are declared in the
document-type shells before the inclusion of the constraint module.

He then integrates the constraint module into the applicable document-type shells and
adds it to his catalog.xml file.